#include <bits/stdc++.h>
#define ios ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define debug  freopen("in.txt","r",stdin),freopen("out.txt","w",stdout);
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 1e6+10;
using namespace std;

int a,b,n;
int main(){
	// debug;
	ios;
	cin>>a>>b>>n;
	cout<<(n-a-1)/(b-a)*2+1<<'\n';
	
	return 0;
}